基于桉树矿质营养吸收特性的平衡施肥模式

Balanced fertilization mode for Eucalyptus robusta based on its nutrition absorption characteristics

【目的】通过研究桉树矿质营养的吸收特性,拟构建出适合广西自然条件下桉树生产的平衡施肥模式。【方法】以长期定位试验为基础,设不施肥对照(CK)、单施氮磷钾化肥、复合肥(N∶P∶K=15∶15∶15)及桉树专用肥(N∶P∶K=12∶5∶8)4个处理,研究不同施肥处理下桉树吸收养分的规律及其生长特性。【结果】桉树对三大矿质营养元素的吸收量以氮最大,其次是钾和磷;对其他矿质营养的吸收量排序为:钙>镁>硫>锌>硼。现阶段广西的土壤肥力状况在不施肥的情况下,仅依赖土壤矿质营养释放量难以满足桉树的生长需求,且目前氮磷钾化肥、复合肥及桉树专用肥的施用量均无法满足桉树对氮、磷、钾矿质营养的需求,需加大现阶段肥料的施用量。其中,施用量为3.5 kg/株的桉树专用复合肥不但能较好地满足当季桉树对微量矿质营养硼的需求,而且在下茬桉树生长中不必再次追施硼肥。【结论】矿质营养在桉树植株中的分布均以枝梢含量最高,因此在春、夏两季桉树枝梢萌发及快速生长期间,要保障充足、均衡的矿质营养供应,尤其是目前广西桉树人工林土壤肥力贫瘠,实际生产中需加大以硼为主要微量元素桉树专用肥的施肥量或配施有机质肥料才能满足桉树的生长需求。

【Objective】The nutrients absorption characteristic of Eucalyptus robusta were studied, in order to establish a balanced fertilization mode for E. robusta in Guangxi. 【Method】On the basis of long-term E. robusta field experiments,the present experiment was designed, which included four treatments viz., no fertilizer（CK）, single NPK fertilization,compound fertilizer（N∶P∶K=15∶15∶15） and special fertilizer（N∶P∶K=12∶5∶8） for E. robusta. Then, the absorb nutrients and growth characteristic of E. robusta were investigated under different fertilizer treatments. 【 Result 】 The results showed that, N uptake amount was the highest among three major mineral nutrient elements, followed by K and P. Meanwhile,the uptake amount of other mineral nutrients were in order as follows： Ca〉 Mg〉 S 〉Zn 〉B. In addition, only depending on nutrients released from unfertilized soil, E. robusta couldn＇t grow well because of lacking more mineral nutrients in present soil. However, at present, the chemical fertilizers applied in E. robusta forest land, including N fertilizer, P fertilizer, K fertilizer, NPK compound fertilizer and special fertilizer for eucalyptus, were not enough for growth of E. robusta. Thus, it was imperative to increase application amount of fertilizers for E. robusta. And the application amount of special compound fertilizer for eucalyptus was 3.5 kg per plant, so as to provide microelement B for growth of E. robusta. And B fertilizer needn＇t be applied again in next cultivation. 【Conclusion 】As for E. robusta plant, the content of mineral nutrition in the tip of branch is the highest. Therefore, because the topmost part of E. robusta can fast grow in spring and summer, the adequate and balanced mineral nutrition should be supplied during two fast-growing periods. Most of all, at present, based on poor soil fertility of artificial forest in Guangxi, the application amount of special fertilizer with microelement B or organic fertilizer should be increased to meet growth requirements of E. robusta in the actual production.